HOSPITAL

Parenteral route

The routes of drug administration created by tissue penetration are called parenteral routes. Parenteral administration allows obtaining systemic effects (intravenous, subcutaneous, intramuscular, intraperitoneal, etc.) or local (infiltrations, intraarterial, intrathecal, intraarticular) effects. Parenteral ways (artificial, by injection) can be divided into three groups:

• extravascular;
• intravascular;
• intraserous.

Extravascular pathways

• the intradermal route - small volume of solution (0.02-0.1 ml) on the anterior face of the forearm, it is used for the purpose of testing the body's sensitivity or for desensitization;
• subcutaneous route (hypodermic) - volume 1-2 ml sterile, non-irritating, isotonic solutions, with a pH close to neutrality in the subcutaneous tissue, from where the substance is absorbed through the blood and lymphatic capillaries. Injections can be painful due to the rich sensory innervation.
• the intramuscular route - the muscles have a rich vascularization, rapid absorption, reduced sensory innervation, less painful. Aqueous, oily solutions, irritating substances with a pH equal to or different from that of plasma are used, in the amount of 1-10 ml. The intramuscular route can also be used for the administration of depot (delayed) drugs. In infants and young children - restraint, risk of muscle fibrosis and atrophy.

Intravascular routes

• the intravenous route - is characterized by rapid and complete absorption of the drugs, with the prompt appearance of the therapeutic effect. It is used in medical-surgical emergencies. Isotonic, hypertonic aqueous solutions can be used, with a pH equal to or different from that of plasma. They will not use oily solutions, hypotones, emulsions, suspensions, hemolytic substances! The intravenous route can also be used for the administration of large amounts of medicine, over a long period of time, at a slow rate => by infusion.
• the intra-arterial route – allows obtaining a higher concentration of the drug at the level of the targeted organ, compared to intravenous administration. In practice, the substances used in radiological diagnosis are also administered intraarterially. The main field of application of this mode of drug administration is cancer chemotherapy. This way ensures, on the one hand, the increase of the antineoplastic concentration in the tumor area, and on the other hand, the decrease of its concentration in the systemic circulation with the corresponding reduction of adverse effects and the increase of the therapeutic index.
• the intracardiac route – used in emergencies, for resuscitation;
• the intraosseous route – provides for the introduction of substances into the marrow of short or wide bones (sternum, iliac bone, femur). The effect sets in very quickly and is equivalent to that registered with intravenous administration. It is used only for general actions of the drug, especially in pediatrics, in special situations. Physiological solutions, plasma, blood can be administered intraosseously.

Intraserous routes

Serous membranes are membranes that line the closed cavities of the body and cover the abdominal organs, foci and joints. They are formed by two sheets between which there is a capillary space containing transudated plasma.

·  intraperitoneal route – medicinal substances administered intraperitoneally are absorbed in full volume. This route of drug administration is rarely used because of the pain caused by the injection, the high risk of infection and the formation of adhesions.

·  the intrapleural route – it is used in a limited way and is intended for local treatment;

·  the intrapericardial route – it is of limited use and is intended for local treatment;

·  the intra-articular route – for local treatments at the level of the joints.;

·  the intraspinal route – medicinal substances are injected into the cerebrospinal fluid by inserting the needle between the L2-L5 lumbar vertebrae. Local anesthetics are administered intrathecally in order to obtain spinal anesthesia; contrast substances for diagnosis; cytotoxic in case of leukemia involving the central nervous system; morphine in acute and chronic pain.